The flag used by the Mengjiang United Autonomous Government consists of a horizontal colour pattern of yellow, blue, white, red, white, blue and again yellow.
The colors on the flag were used to represent major ethnic groups in Mengjiang: blue for the Mongols; red for the Japanese; yellow for the Han and white for the "Hui" (the name given to the Muslims at that time).
South Chahar, North Shanxi and the Mongol Military Government each had their respective flags before merged with the Mengjiang United Autonomous Government.
The colors on the flag of Mengjiang is similar to the Five Races Under One Union flag formerly used by the Republic of China. The flag is also similar in both colour and pattern to the flag used by the Young China Party.